<template>
  <span v-if="obj.result===null" class="undo">1: 未完成</span>
  <span v-else-if="obj.result===obj.left+obj.right" class="right">1: 正确</span>
  <span v-else class="error">1: 错误</span>
</template>

<script>
export default {
    props:{
        obj:{
            type:Object,
            required:true,
        }
    }
};
</script>

<style scoped>
.right {
  color: green;
}
.error {
  color: red;
}
.undo {
  color: #ccc;
}
</style>